How many watts for a 1hr / 40km TT

Triathlon Forum
46

"I thought I had a fairly low and aggressive position (arm pads 15 cm down from the saddle) until some trials indicated that my CdA was 0.29. I’ve now got the pads 21 cm down, and my elbows 4 cm closer together and I think I’m down closer to 0.26. "

Hi Rick,

I spoke with Scott Martin about this, and was interested in how one goes about estimating their CdA. Where did you do your testing, and how did you determing the CdA? Accurate CdA numbers would help me to determine if my calculations on Analyticcycling are on mark.

I have been using the .25/.25 values (my new position is much more agressive than my 2004 position, and I have a new frame, aerobars, front brake, skinsuit and helmet), but have no idea of the validity of these numbers.

Thanks

  • Gary
47

Hi Gary,

Your best bet to guesstimate your CDa is to fill in the other variables in the equation, to the best of your ability, and then back-fill Cda in Ana.Cyc. to make the numbers work.

I have riders ride at a known wattage, for a known time, which gives us a known distance, on a known surface, under “as neutral as possible” conditions, and fill in Cda from the results of several tests (further refined over time.)

In other words, get out to the velodrome on a calm day with your PT, and have at it. Wash, rinse, repeat.

.

48

You are right, that velodrome test would be a guess!

How accurate can that measurement be I wonder?

Lots of time would need to be spent riding laps, over and over, timing myself.

49

It’s not a guess, it’s an estimate - and there IS a difference.

You can get a good idea of the margin of error for this type of test by re-reading the AC bike test on BTR. The MOE is well within the useful range for what you are doing, and is refine-able over time (like, with every single TT you do…)

Sure, it takes time. Would you rather use that time fishing on the internet for a “guess,” or do the work to come up with an estimate? Your choice… (and, really, it isn’t that time consuming to come up with a better set of numbers than just using the default…)

From what you have posted earlier, you are basing your entire season’s training on a Cda number, and resultant wattage figure, that is pure, unadulterated guesswork. I wouldn’t feel comfortable with that, but, hey, that’s just me!

  • I AM NOT WRITING THIS TO BE A JERK!!!-

Remember Palomar? I asked how you got your target wattage, and well, basically, you just guessed at it -and blew up.

In all honesty, this was a really cool example for me, as a coach, and I thank you for being so candid, and providing the file. I am still in the process of crystallizing my views on wattage training, and you may have provided me with an excellent “con” or more appropriately, “learn from this” example.

To witt:

target wattage was chosen by desired time to finish, rather than by previously demonstrated cp60.

Rider was unable to maintain wattage, and fell below pace early, ultimately falling well below previously established CP level (which was significantly lower than target wattage.)

Result was potentially due to unrealistic CP, and was (potentially) a slower time than if rider had ridden to PE levels.

All very interesting, to me at least.

Thanks Gary, and apologies for drifting OT

.

50

"Remember Palomar? I asked how you got your target wattage, and well, basically, you just guessed at it -and blew up. "

I didn’t just guess at it, it was reccomended by my coach, based on my goal time of 1:10 that I wanted to reach.

I was only 4 minutes off, and might have reached my goal had I not cramped so badly near the top.

Use this as a case study instead, better scenerio of a cyclist trying to ride harder than he “can”!

http://www.cyclingnews.com/track.php?id=track/2003/jul03/hutchinsonhour03 Michael Hutchinson’s Hour Record Attempt Manchester Velodrome, UK, July 2, 2003 Hutchinson abandons Hour Record try after 40 minutes

By Nick Rosenthal

Ready
Photo: © Nick Rosenthal http://www.cyclingnews.com/photos/2003/jul03/hutchhourattempt/NDR_Hutch007tn.jpg

British time trial champion Michael Hutchinson yesterday failed in his attempt to break the most-prized record in cycling, the Hour, currently held by Chris Boardman who recorded an official distance of 49.441872km here during the 2000 world track championships. Riding an all-steel track bike in the colours of his sponsor Giant, Hutchinson made a valiant effort, but was consistently down on Boardman’s times and climbed off after 40 minutes, by which point he was about two minutes down on Boardman.

In action
Photo: © Nick Rosenthal http://www.cyclingnews.com/photos/2003/jul03/hutchhourattempt/NDR_Hutch022tn.jpg

Several times during the ride, Michael Hutchinson showed signs of discomfort, his hands moving to the top of the bars to give his arms a rest from the 1970s ‘down on the bends’ position. He gave it his all for 40 minutes, but then acknowledged that he was not going to pull back a two minute deficit and brought his attempt to an end. Hutchinson drew to a halt in the back straight, visibly exhausted, spending a few moments getting his breath back and composing himself before waving to the crowd and expressing his thanks for their support and applause.

Thankyou
Photo: © Nick Rosenthal http://www.cyclingnews.com/photos/2003/jul03/hutchhourattempt/NDR_HutchThankstn.jpg

Although he was not quite on the pace at the Manchester Velodrome this evening, he was not very far off it. Hutchinson is an intelligent rider, known for his scientific and methodical approach, so it is possible that he may choose to analyse the data from this evening’s attempt on the world hour record and have a careful think about trying again at some stage.

*Images by Nick Rosenthal/www.fatnick.com * Michael Hutchinson waves to the crowd in the Manchester velodrome before the start of his record attempt. In the cage and ready for the off Off to a solid start in the deep tuck ‘Eddy Merckx’ position now required by UCI rules. The form that has made Hutchinson one of the UK’s most respected time trialists. Hugging the very edge of the inside line Maintaining a deep tuck for an hour was one of the hardest parts Close to 40 minutes in and two minutes down on Boardman’s record Hutchinson acknowledges the support of the crowd after abandoning his attempt

51

Curious as to why he would be using those wheels if he was making a serious attempt? Wouldn’t a disk be better?

52

If only I had his PM file!

.

53

"Curious as to why he would be using those wheels if he was making a serious attempt? Wouldn’t a disk be better? "

Hour record attempt.

54

There was a whole raft of regulations Hutchinson had to ride under.

Basically the UCI were trying to take the bike out of the equation - so it wasnt radically different from Merckx era bikes.

Makes sense to me then we know its the rider not the bike.

Now they’ve relented and you saw Jens breaking the record on a modern bike. How much was Jens ? How much was the bike ?

55

Contender for oldest thread resurrection?! Only a few months short of a decade!